<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<script src="https://cdn.staticfile.org/jquery/1.10.2/jquery.min.js">
</script>
<script>
$(document).ready(function(){
  $("button").click(function(){
    $("#div1").fadeTo("slow",0.15);
    $("#div2").fadeTo("slow",0.4);
    $("#div3").fadeTo("slow",0.7);
  });
});
</script>
</head>

<body>
<p>演示 fadeTo() 使用不同参数</p>
<button>点我让颜色变淡</button>
<br><br>
<div id="div1" style="width:80px;height:80px;background-color:red;"></div><br>
<div id="div2" style="width:80px;height:80px;background-color:green;"></div><br>
<div id="div3" style="width:80px;height:80px;background-color:blue;"></div>

</body>
</html>